The hurricane, now a Category Three storm with sustained winds of 120mph (193km/h), is heading up the coastline of the US state of Florida.

At 07:00 local time (11:00 GMT) Matthew was still off the shore, centred about 25 miles (40km) east of Cape Canaveral and proceeding north north west at around 14mph (22km/h), the National Hurricane Center said. It remains uncertain whether it’ll make landfall.

Hurricane Matthew has thumped the Bahamas after slicing through Cuba and Haiti. Trees and power lines were apparently down in the Bahamas but no fatalities were reported.

Most of the departures in Haiti were in fishing villages and towns around the southern shore, with many killed by falling trees, flooding rivers and flying debris.

The thunderstorm passed right through the Tiburon peninsula, driving the sea inland and flattening houses with winds of up to 230km/h (145mph) and torrential rain on Monday and Tuesday.

The failure of an important bridge on Tuesday had made the southwest mostly cut off.

Non-governmental organisations said people were running out of food and water and electricity and mobile coverage were down. The BBC’s Tony Brown in southwestern Haiti said he’d seen people attempting to handle the mass destruction by themselves, attempting to reconstruct from the debris minus assistance from authorities or the military.

Across the country, there were some 350,000 in need of help, according to the UN Office for the Coordination of Humanitarian Affairs.

Suzy DeFrancis, a representative for the American Red Cross, said the first priority was to get mobile networks across the country back ready to go. “We’ll bring in technology to help do that,” she said.

“We also have warehouses with aid materials that we’ll be doling out. Some of the needs that families may have are kitchen kits to allow them to cook meals, any type of hygiene kits and then we’re most worried about cholera, so we’ll be helping distribute aqua tabs to purify the water.”

The US is sending nine military helicopters to help deliver water and food to the hardest-hit regions. The state is among the world’s lowest, with many residents living in flimsy home in flood-prone regions. Four people also perished on Tuesday in the thunderstorm in the neighbouring Dominican Republic.

‘Waves your roof over’. In the US, evacuation orders have been issued for areas.